modelAirToWater

Information

This model validates Buildings.Templates.Plants.Controls.HeatPumps.AirToWater in a configuration with three equally sized lead/lag alternate heat pumps and a sidestream heat recovery chiller.

Simulating this model shows how the controller responds to a varying load by

enabling the sidestream HRC in cooling mode,
staging or unstaging the AWHPs and associated primary pumps,
rotating lead/lag alternate equipment to ensure even wear,
resetting the supply temperature and remote differential pressure in both the CHW and HW loops based on the valve position,
staging the secondary pumps.

Parameters

Type	Name	Default	Description
Nominal condition
Real	capHea_nominal	sum(ctl.capHeaHp_nominal)	Installed heating capacity
Real	THeaWatSup_nominal	323.15	Design HW supply temperature
Real	THeaWatRet_nominal	315.15	Design HW return temperature
Real	VHeaWat_flow_nominal	capHea_nominal/abs(THeaWatSup_nominal - THeaWatRet_nominal)/ctl.cp_default/ctl.rho_default	Design HW volume flow rate
Real	capCoo_nominal	sum(ctl.capCooHp_nominal)	Installed cooling capacity
Real	TChiWatSup_nominal	280.15	Design CHW supply temperature
Real	TChiWatRet_nominal	285.15	Design CHW return temperature
Real	VChiWat_flow_nominal	capCoo_nominal/abs(TChiWatSup_nominal - TChiWatRet_nominal)/ctl.cp_default/ctl.rho_default	Design CHW volume flow rate

Components

Type	Name	Description
Buildings.Templates.Plants.Controls.HeatPumps.AirToWater	ctl	Plant controller
Buildings.Controls.OBC.CDL.Reals.Sources.TimeTable	ratV_flow	Source signal for volume flow rate ratio – Index 1 for HW, 2 for CHW
Buildings.Controls.OBC.CDL.Reals.Sources.Constant	dTHeaWat	HW Delta-T
Buildings.Controls.OBC.CDL.Reals.Sources.Constant	dTChiWat	CHW Delta-T
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	VHeaWat_flow	Scale by design flow
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	VChiWat_flow	Scale by design flow
Components.Controls.StatusEmulator[ctl.nHp]	y1Hp_actual	HP status
Components.Controls.StatusEmulator[ctl.nPumHeaWatPri]	y1PumHeaWatPri_actual1	Primary HW pump status
Components.Controls.StatusEmulator[ctl.nPumChiWatPri]	y1PumChiWatPri_actual	Primary CHW pump status
Components.Controls.StatusEmulator[ctl.nPumHeaWatSec]	y1PumHeaWatSec_actual	Secondary HW pump status
Components.Controls.StatusEmulator[ctl.nPumChiWatSec]	y1PumChiWatSec_actual	Secondary CHW pump status
Buildings.Controls.OBC.CDL.Reals.Sources.Sin	TOut	OAT
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold	isDemHea	Return true if heating demand
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold	isDemCoo	Return true if cooling demand
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger	reqPlaHeaWat	Generate HW plant request
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger	reqPlaChiWat	Generate CHW plant request
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter[2]	gai	Use fraction of flow rate as a proxy for plant reset request
Buildings.Controls.OBC.CDL.Conversions.RealToInteger	reqResHeaWat	Generate HW reset request
Buildings.Controls.OBC.CDL.Conversions.RealToInteger	reqResChiWat	Generate CHW reset request
Buildings.Controls.OBC.CDL.Reals.Sources.Sin[1]	sin	Source signal used to generate measurement values
Buildings.Controls.OBC.CDL.Reals.Add[1]	dpHeaWatRem	Differential pressure at remote location
Buildings.Controls.OBC.CDL.Reals.Add[1]	dpChiWatRem	Differential pressure at remote location
Pumps.Generic.ResetLocalDifferentialPressure[1]	resDpHeaWatLoc	Local HW DP reset
Pumps.Generic.ResetLocalDifferentialPressure[1]	resDpChiWatLoc	Local CHW DP reset
Buildings.Controls.OBC.CDL.Reals.Sources.Sin[1]	sin1	Source signal used to generate measurement values
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	dpHeaWatLoc	Differential pressure local to the plant
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	dpChiWatLoc	Differential pressure local to the plant
Components.Controls.StatusEmulator	y1Hrc_actual	Sidestream HRC status
Buildings.Controls.OBC.CDL.Reals.Sources.Constant	dTHeaWatUpsHrc	HW Delta-T as measured upstream of HRC
Buildings.Controls.OBC.CDL.Reals.Sources.Constant	dTChiWatUpsHrc	CHW Delta-T as measured upstream of HRC
Buildings.Controls.OBC.CDL.Reals.Add	THeaWatRet	HWRT
Buildings.Controls.OBC.CDL.Reals.Add	THeaWatRetUpsHrc	HWRT upstream of HRC
Buildings.Controls.OBC.CDL.Reals.Add	TChiWatRet	CHWRT
Buildings.Controls.OBC.CDL.Reals.Add	TChiWatRetUpsHrc	CHWRT upstream of HRC

Revisions

March 29, 2024, by Antoine Gautier:
First implementation.